A vehicular headlamp known in the art is provided with a lamp unit which includes, for example, a light source disposed within a lamp casing configured by, for example, a cover and a lamp housing.
In the lamp unit of the vehicular headlamp, a light quantity control mechanism configured to control a light quantity emitted from the light source is provided and the light quantity control mechanism includes a movable shade configured to change the shielding quantity of the light emitted from the light source and a solenoid configured to operate the movable shade. See, e.g., FIG. 4 of Japanese Patent Laid-Open Publication No. 2007-213938.
In the vehicular headlamp disclosed in Japanese Patent Laid-Open Publication No. 2007-213938, an output shaft of the solenoid disposed in front of the solenoid and the movable shade disposed behind the solenoid are connected with each other by a wire type arm and the movable shade is configured to be rotatable on a rotation shaft extending to the left and the right as a fulcrum. When the output shaft of the solenoid moves in the left and right direction, the arm is rotated and the movable shade turns on the rotation shaft as a fulcrum with the rotation of the arm.
When the movable shade turns to a first position, the irradiation mode is switched into a low beam irradiation mode that irradiates a short distance. When the movable shade turns to a second position, the irradiation mode is switched into a high beam irradiation mode that irradiates a long distance.
In the vehicular headlamp disclosed in Japanese Patent Laid-Open Publication No. 2007-213938, the output shaft of the solenoid is disposed to be movable in the left and right direction and the rotation shaft of the movable shade is also disposed such that the axial direction of the rotation shaft corresponds to the left and right direction. Thus, the size of the vehicular headlamp may be reduced in the front and rear direction.